Lightweight, High-Strength Hybrid Gear

mechanical and fluid systems
Lightweight, High-Strength Hybrid Gear (LEW-TOPS-41)
Can optimize performance of gear systems
Overview
The components used in rotorcraft applications are designed to be lightweight without sacrificing reliability or safety. Since the drive system is an appreciable percentage of the overall rotorcraft vehicle weight, many tactics have been used to improve the power to weight ratio of these components. Innovators at NASA's Glenn Research Center have developed a method for incorporating lightweight, high-strength composites into the gears of rotorcraft drive systems. Although specifically designed for use in rotorcraft, this hybrid gear has potential in many other large gear applications. The composite material serves to lighten the gear while transferring the same level of torque found in all-metallic gearing. Through the careful selection of composite materials and ply layups, the design of the hybrid gear can be optimized to reduce the noise and vibration typical of gear systems.

The Technology
The use of composites in a rotorcraft drive system, with their low density and high strength, can improve power to weight ratio. NASA Glenn inventors have succeeded in reducing the weight of large-scale gears for rotorcraft and other applications, which are conventionally machined from forgings, by using composite material as the web of the gear between the gear teeth and a metallic hub. The hybrid gear has a metallic shaft and outer gear rim, with composite layup between the shaft interface and the gear tooth rim. The Hybrid Gear was built and tested at NASA Glenn and found to be 20% lighter than all-steel gears. In an endurance test consisting of over 300x106 gear revolutions at 10,000 RPM and 250 PSI torque load, the hybrid gear operated without problem and showed no fatigue in post-test inspection. Through the use of various composite materials and ply layups, this hybrid gear fabrication method can accommodate complex shapes. Hybrid gear designs can also be tailored to optimize mechanical and acoustic performance, while reducing noise and critical vibration modes.
Military MV-22 Osprey Glenn's hybrid gear design can be optimized to reduce noise and vibration
Benefits
  • Lighter: Found to be 20% lighter than all-metallic gears
  • Quieter: Optimized designs can lower gear noise and vibration
  • Cheaper: Less machining of forgings required
  • Robust: Composite materials can accommodate complex geometries

Applications
  • Aerospace
  • Military
  • Automotive
  • Construction equipment
  • Wind turbines
Technology Details

mechanical and fluid systems
LEW-TOPS-41
LEW-18516-1
9,296,157
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